Resin-based casting compounds that cure by a chemical reaction play a major role in the production of industrial components and assemblies. They are used for insulation purposes in electric and electronic components, among other things. If such a component heats up during operation, adequate dissipation of heat must be ensured. If heat is generated directly in the printed conductors of the component, casting compounds having a high thermal stability and a high thermal conductivity are desirable for use for insulation or mechanical fixation.
German Patent No. 41 38 411 describes curable casting compounds which are used for mechanical fixation and dissipation of heat for windings of water-cooled generators. However, the casting compounds described there are two-component systems having a thermal conductivity of 0.8 to 1.8 W/mK.
In two-component systems, one component is an activator, which is mixed with the other component, which contains reactive resins, fillers, etc., and the mixture is processed immediately. This is a disadvantage, because preparation of the casting compound must be integrated into the processing operation, and it is impossible to store the ready-to-use mixture for three to twelve months at room temperature, for example. Another disadvantage is that it is technically very difficult to ensure the occupational safety in handling the activating component, because the compounds used as activators, e.g., anhydrides of carboxylic acids or amines, are often irritants or represent a health hazard. For this reason, there is interest in the development of casting compounds in the form of single-component systems which are storable for long periods of time in the premixed form.
The object of the present invention is to provide a casting compound which is stable in storage and is directly processable as a single-component system, having good flow properties during processing and a high thermal stability and thermal conductivity.